Chem 8- Periodicity Flashcards
(15 cards)
What are elements in groups 1-3 classed as?
They are all metals
As silicon in group 4 has 4 electrons in the outer-shell, what does it form?
It forms 4 covalent bonds.
What is Silicon classes as?
A semi-metal
What are elements in groups 5-7 classed as?
Non-metals
What happens to the melting and boiling points going across period 3, and why?
The melting and boiling points increase because of the metalic bonding strength.
As you go from left to right on period 3 what happens to the charge on the ions?
The charge on the ions increases so more electrons join the delocalised electron sea that holds the giant lattice together.
In period 3, the melting point of the non-metals with molecule structures depend on what?
The sizes of the Van Der Waals forces between the molecules and this depends on the number of electrons in the molecule and how closely they can pack together
What structure do elements in group 1,2 and 3 have?
Giant metallic
What structure do elements in group 4 have?
Giant covalent
What structure do elements in groups 5,6 and 7 have?
Molecular
What structure do elements in group 8 have?
Atomic
What happens to the atomic radium across a period and why?
It decreases because:
- there are more protons and electrons on the outer shell
- more effective nuclear charge
- atoms get smaller
What happens to the ionisation energy across a period?
It increases because:
- number of protons increase so more effective nuclear charge
- much harder to remove an electron
Why is there a steep drop in ionisation energy between groups 2 and 3?
Jumping from magnesium to aluminium is changing blocks from the S block to the P block.
The P electron is already in a higher energy level than the S electron so it takes less energy to remove.
Why is there a steep drop in ionisation energy between groups 5 and 6?
In group 6, the electrons in the orbitals begin to pair up. An electron in a pair is easier to remove than one in its own orbital and it is already being repelled by another electron.
